A 58-year-old male farmer from rural Maharashtra presents to the primary health centre with a 6-month history of exertional chest discomfort and dyspnea. He has never smoked but chews tobacco daily for the past 20 years. His father died of myocardial infarction at age 62. On examination, BP is 148/94 mmHg, heart rate 88/min regular. Fasting blood glucose is 126 mg/dL, total cholesterol 245 mg/dL, LDL 165 mg/dL, HDL 32 mg/dL, triglycerides 180 mg/dL. ECG shows nonspecific ST-T changes. Based on the epidemiology of cardiovascular disease in India, which single modifiable risk factor accounts for the largest attributable population risk in this patient's presentation?

Explanation

## Epidemiology of CVD Risk Factors in India **Key Point:** Hypertension is the leading modifiable risk factor for cardiovascular disease in the Indian population, accounting for the highest population attributable risk (PAR) in both urban and rural settings. ### Population Attributable Risk (PAR) in India According to the Global Burden of Disease Study and Indian epidemiological data: | Risk Factor | PAR (%) | Prevalence in India | |---|---|---| | Hypertension | 35–40% | 25–30% in adults | | Dyslipidemia | 20–25% | 30–35% in urban areas | | Tobacco use | 15–20% | 28.6% (any form) | | Diabetes/IFG | 10–15% | 8–10% | | Obesity | 5–10% | 5–10% | **High-Yield:** PAR = Prevalence × (Relative Risk − 1) / [1 + Prevalence × (RR − 1)]. A factor with both high prevalence AND high relative risk dominates population burden. ### Why Hypertension Leads in India 1. **Prevalence:** 25–30% of Indian adults have hypertension; it is underdiagnosed and undertreated. 2. **Relative Risk:** Hypertension increases CVD risk 2–3 fold; this is consistent across populations. 3. **Combined burden:** High prevalence × moderate-to-high RR = largest PAR. **Clinical Pearl:** In this patient, BP 148/94 mmHg (Stage 2 hypertension) is present alongside other risk factors. However, at the *population level*, hypertension's prevalence and attributable risk exceed those of dyslipidemia, tobacco, or glucose intolerance in India. ### Why Other Options Are Secondary - **Tobacco use (chewing):** PAR ≈ 15–20%; prevalence is high (28.6% any form), but relative risk for CVD is lower than for lung cancer. In this patient, 20 years of chewing is a strong individual risk, but population-wide, fewer people chew than have hypertension. - **Dyslipidemia:** PAR ≈ 20–25%; prevalence is high in urban India (30–35%), but rural populations (like this patient) have lower lipid levels on average. Dyslipidemia is a strong risk factor, but hypertension's prevalence is more uniform across rural and urban India. - **Impaired fasting glucose:** PAR ≈ 10–15%; prevalence is lower (8–10%) and RR is moderate; it contributes less to population burden than hypertension. **Mnemonic:** **HATED** — Hypertension, Alcohol, Tobacco, Exercise (lack), Diet (poor). Hypertension is first because it has the highest PAR in India. [cite:Park 26e Ch 10]